Air quality alerts are in effect on Tuesday in 10 states as toxic smoke from hundreds of wildfires burning in Canada continues to waft into the United States, creating hazy, gray skies over major metropolitan areas, including New York City.

Smoke from Canadian wildfires is causing air quality concerns for millions of Americans in the Midwest and Northeast. Air quality alerts were in effect Tuesday in several states, including Wisconsin,

Air quality alerts were issued in North Jersey Aug. 5 as smoke from Canadian wildfires drifts across the northern United States.